Phosphorus Nutrition as a Factor Influencing Photosynthesis in Maize Plants II. The Effect of Phosphorus Level on the Primary Metabolites and on the Carbon Flow to the End Products of Photosynthesis

Abstract

Summary Products of 14CO2 assimilation were examined in leaves of maize seedlings with decreased phosphorus content but unchanged photosynthesis rate. The phenomenon of light-enhanced dark 14CO2 fixation (LED) was used to examine the early products. It was found that at a low phosphorus level the ratio of the aspartate/malate radioactivities increased; also, there was an acceleration of flow of assimilated carbon from the primary and intermediate metabolites to the end products of photosynthesis. Starch production was lowered, whereas synthesis of monosaccharides and sucrose increased.